HE NOSE HIS JOBA: Joba Chamberlain had a look of determination last night. Though he didn’t get the whiff, he did induce an inning-ending grounder by Delmon Young, the only batter he faced, in last night’s 7-2 win over the Twins in Game 1 of the ALDS in The Bronx.REUTERS

On the last day of the season, Joba Chamberlain went back to the bullpen. Three outs, no problem.

Last night, he was in the ‘pen again for ALDS Game 1. One out, no problem.

Chamberlain, whose role has been debated back and forth for two-plus years, closed out the eighth inning of the Yankees’ 7-2 victory over the Twins. He entered with one on and two outs in the inning and retired Delmon Young on a harmless force play.

If you’re keeping track, Chamberlain’s faced four batters in relief this season — four up, four down.

Chamberlain has been a dominant reliever in his career, and for this round at least, his return makes the Yankees’ bullpen almost frightening. Last night, he was part of a crew that included Phil Hughes, Phil Coke and Mariano Rivera, who combined to hurl 21⁄3 innings of scoreless ball.

Hughes recorded the biggest out for the bullpen, staving off a potential Twins rally the same way he helped fend off Yankees elimination in the 2007 playoffs.

Cabrera, who hit a monster home run in the seventh inning in the Twins’ dramatic one-game playoff win over the Tigers one night before, came up in the seventh, poised to turn a 6-2 Yankees lead into a cause for Bronx concern.

The Twins had two on, two out and — worst of all — Joe Mauer on deck. But Hughes suffocated the rally, battling through a 10-pitch at-bat to strike out Cabrera and end the threat.

Hughes had pitched in the postseason two times before, including Game 3 of the 2007 ALDS against the Indians, when he picked up the win with 32⁄3 innings of scoreless relief. But this series amounts to a different atmosphere — and a different role — for the 23-year-old right-hander. Hughes is now the Yankees’ chief setup man, and being responsible for October’s late innings is an extraordinarily critical role.

Hughes was dominant in that capacity during the season, posting a 1.40 ERA in 44 relief outings. And the Yankees weren’t worried about how he would fare in the playoffs.

“He has been in the playoffs before,” Rivera said Monday. “If I have to say something, I will. But I think he’s prepared.”